Abstract: The catalytic reaction mechanism of oxidation of p-xylene to terephthalic acid with Co-Mn-Br catalyst was presented，and the promotion and side effect of Br ions in oxidation of p-xylene was discussed. The research on promotion of oxidation of p-xylene by organic precursor to reduce the use of Br ions could alleviate corrosion of equipment and reduce the emission of bromide，realizing good economic and social benefits. A new practical application catalyst system for p-xylene oxidation was developed during the research on the promotion of oxidation reaction by a free-radical precursor by simulating the actual production of terephthalic acid (PTA) with p-xylene (PX) and intermediate p-toluic acid (PT acid) as raw materials. The new catalyst passed industrial test. The results showed that adding 40 ×10?6 additive into the reaction system could keep the concentrations of Co and Mn unchanged and reduce the concentration of Br ions from 500 ×10?6 to 250 ×10?6.

Key words: terephthalic acid, catalytic reaction, free radical, additive

摘要： 介绍了Co-Mn-Br催化对二甲苯氧化生产对苯二甲酸的反应历程，阐述了溴元素在对二甲苯的甲基氧化过程中的促进作用及带来的负面影响。研究通过添加剂促进对二甲苯氧化，减少溴的用量，对于减轻设备腐蚀、减轻溴排放具有重要的意义。本文先以对二甲苯（PX）和中间产物对甲基苯甲酸（PT酸）为原料，模拟对苯二甲酸（PTA）生产过程中氧化反应器中实际组成状况，通过自由基前体型添加剂对氧化反应促进的研究，开发出适合生产应用的对二甲苯氧化催化剂新体系，并进一步通过工业试验验证。结果表明，在保证PX氧化反应效果不变的前提下，反应体系中添加40×10?6的添加剂可以实现保持Co-Mn-Br三元催化剂中钴、锰浓度不变，氢溴酸使用浓度从500 ×10?6降低到250×10?6。

关键词: 对苯二甲酸, 催化反应, 自由基, 添加剂